Technical Field
The invention relates to a method for accessing a memory, and particularly, the invention relates to a method for reducing a row hammer effect of a memory.
Related Art
In a specific application of a dynamic memory, a specific word line therein is probably required to be repeatedly turned on by many times. In this case, data stored in memory cells on word lines adjacent to the word line that is repeatedly turned on by many times is probably varied due to a cross talk effect or a coupling effect, and the situation mentioned above is called row hammer effect.
In detail, referring to FIG. 1, FIG. 1 is a schematic diagram of a dynamic memory having a row hammer effect. When the word line WLA is repeatedly turned on by many times during two adjacent refresh operations, the memory cells on the word lines WLB and WLC adjacent to the word line WLA may have a data error phenomenon due to the repeat turn-on operations of the word line WLA. The word lines WLB and WLC can be referred to as victim word lines, and the word line WLA can be referred to as an aggressor word line.
In the conventional technical field, additional refresh operations are generally performed to resolve the aforementioned problem of the row hammer effect. However, such solution cannot be implemented in burst type refresh operations. Moreover, to cope with the additional refresh operations to be performed, the specification of the dynamic memory is required to be modified, which may cause usage difficulty.